Portable workbench for powerdriven hand and table tools



T. L. DIRKSEN June 3, 1952 PORTABLE WORKBENCH FOR POWER-DRIVEN HAND AND TABLE TOOLS Filed July 7, 1950 8 Sheets-Sheet l nlrll INVEN TOR.

w W w m D T m E 1 m L m DRIVEN HAND AND TABLE TOOLS 8 Sheets-Sheet 2 June 3, 1952 r. DIRKSEN PORTABLE WORKBENCH FOR POWER- Filed July 7, 1950 I N V EN TOR. THE RE L- RK EN mm 0 PP P0 P0 00 x HP 00 92..

AT T O RNEY T. L. DIRKSEN 2,599,096

PORTABLE WORKBENCH FOR POWER-DRIVEN HAND AND TABLE TOOLS June 3, 1952 8 Sheets-Sheet 3 Filed July '7, 1950 INVENTOR. THEODORE 1,. mmgsnn Ant F June 3, 1952 T. L. DIRKSEN 2,599,096

PORTABLE WORKBENCH FOR POWER-DRIVEN HAND AND TABLE TOOLS Filed July 7, 1950 8 Sheets-Sheet 4 IN V EN TOR. [wmx R/ L IR EN June 3, 1952 D|RKsEN 2,599,096

PORTABLE WORKBENCH FOR POWER-"DRIVEN HAND AND TABLE TOOLS Filed July 7, 1950 8 Sheets- Sheet 5 INVENTOR. TfiEODORE LDIRB EN ATTORNW June 3, 1952 T. DIRKSEN 2,599,096

PORTABLE WORKBENCH FOR POWER-DRiVEN HAND AND TABLE TOOLS Filed July 7, 1950 8 Sheets-Sheet 6 I \-H 89 1mg it;

A 88 r I l 7 I N VEN TOR. 2 THE RE 1 IKE N BY ATTOIFUVEY June 3, 1952 1'. L. DIRKSEN PORTABLE WORKBENCH FOR POWER-DRIVEN HAND AND TABLE TOOLS 8 Sheets-Sheet '7' Filed July 7, 1950 INVENTOR. THEODORE L- IRKSJ N |||||l m 00 l DRIVEN HAND AND TABLE TOOLS T. DIRKSEN June 3, 1952 PORTABLE WORKBENCH FOR POWER- Filed July 7, 1950 8 Sheets-Sheet 8 INVENTOR. THEODORE LDIRKSEZN ATTORNEY tion, the jointer being shown in its operative position; 7

Figure 2 is a longitudinal sectional View taken substantially on line 2-2 of Fig. 1;

Figure 3 is a transverse sectional view taken substantially on line 3-3 of Fig. 1;

Figure 4 is a sectional View taken substantially on line 4-4 of Fig. 2 and looking down upon actuating mechanism that traverses the saw and its table;

Figure 5 is an elevation of the side of the guidebench upon which a jointer .is mounted to be moved into and out of operative position with the bench, said jointer being shown therein in its stored or inoperative position within the confines of said guide-bench;

Figure 6 is a top plan View of the jointer supporting means carried by said guide-bench and is taken substantially on line 66 of Fig. 5;

Figure 6a is a detail sectional view of mounting for the jointer supporting means and taken substantially on line (Ea-6a of Fig. 5;

Figure 7 is a plan view of the saw table per se as shown in Fig. 1 and of the manner of mounting the same on supporting tracks for reciprocal movement;

Figure 8 is an enlarged detail side View of the saw table actuating mechanism shown in Figuresl, 2 and 5;

Figure 9 is a fragmental underside view of the j work supporting drop-leaf hinged to one side edge of said bench and illustrating the supporting leg therefor and themanner of collapsing and holding it against the underside of said drop-leaf;

Figure 10 is a detail view taken substantially online l0l0 of Fig. 9 and showing the clip employed to hold the supporting leg against said drop-leaf;

Figure 11 is a fragmentary elevation of one of the hinged end wings of the guide bench and the manner of holding it in place when swung to its opposite position from that shown in Fig. 3;

Figure 12 is a detail sectional view taken substantially on line l 2l2 of Fig. 11;

Figure 13 is an enlarged side elevation of one end portion of the ripping-gauge, shown in Figs. 1 and 3, mounted on the dropleaf and is taken substantially on line I3l3 of Fig. l;

Figure 14 is a top plan of said end portion of the ripping-gauge shown in Fig. 13;

Figure 15 is a detail section view illustrating the. construction of the releasableclamp on one end of said ripping-gauge holding bar and is taken substantially on line l5-l5 of Fig. 14;

Figure 16 is a View similar to Fig. 15 and taken substantially on line 16-46 of Fig. 1. to show the construction of the other end of said rippinggauge holding bar; 7

Figure 17 is a perspective View of the end of the ripping-gauge holding bar shown in Fig. 16;

Figure 18 is a perspective view of the adjust- 4 guide bench and to have a power driven hand or hand saw detachably connected thereto;

Figure 23 is a sectional view taken substantially on line 23-23 of Fig. 22;

Figure 24 is a side elevation'of the saw and its table mounted on the supporting rails of the guide bench, as shown in Fig. 7, but with parts brokenaway to show the chocking-blocks employed to hold the saw-table stationary on said bench, when desired, for doing certain cutting while the saw is held stationary, and is taken substantially on line 2424 of Fig. 25; and

Figure 25 is a detail sectional view taken transversely through the upper left-hand corner of the guide bench shown in Fig. 3 but with the chocking-blocks, shown in Fig. 24, applied.

Throughout the specification and the drawings like characters of reference denote similar like parts.

More specifically, the bench of the present invention is of rectangular construction comprising four corner standards or legs 30, each pair of legs on opposite sides of the bench being connected at their upper ends by top side rails 34 and each pair of legs 30 at the respective ends of the bench being connected intermediate their length by end plates 32 to hold the side portions of the bench rigidly in spaced relation. The bottom ends of the legs 30 are equipped with casters 33 so that the bench may be easily and readily moved from place to place as may be required or desirable. The bench, now constructed in accordance with the present invention, has its side rails 31 seven feet long and is about thirty-six inches high from the supporting surface upon which the casters 33 rest. The overall width of the bench is thirty inches, in its collapsed position-i. e. with the side drop-leaf down and with the jointer disposed within the confines of the bench as presently will be explainedthus enabling the bench to be moved through doorways, halls, aisles of stores and the like. In order to give rigidity to the bench as well as support to other instrumentalities of the bench, as will presently appear, lower side brace rails 34 connect opposite legs on opposite sides, respectively, of the bench at a point spaced from the bottom ends of the legs 30 and which are complemented by lower end brace rails 35 connecting opposite legs 30 at opposite ends of the bench and as a continuation of the side brace rails 34.

While the bench may be constructed of any suitable material, it is preferred that the legs 30 and rails 3| be constructed of light weight metals, such as sheet steel or sheet aluminum strips which are corrugated to add strength and rigidity and which in cross-section are formed right angles, asshown. The lower brace rails 34 and 35 are made of similar material but are straight corrugated pieces asindicated in the drawings. The upper surfaces a of the rails 3| are arranged in alignment-that is, in the same horizontal planeso as to provide a level surface upon which to support material to be operated upon by the saw 36 or other suitable rotating tool.

With the right end of the bench, as shown in Figures 1, 2, 3, 5 and 19, regarded as the front end which the operator faces while operating the tool 36, the bench is provided on its right hand side, as shown more particularly in Figure 3, with a drop-leaf 31 extending the length of the bench and hinged at one of its longitudinal edges, as at 38, to the longitudinal edge portion of the are-at least two rollers 5912, having fiat rimmed. treadsprovided for tractional support by the rollers 59a extending through one leg of an elongated inverted U-shaped bracket 62 and the axles of rollers 60a being similarly carried by another bracket 62. There is interposed between the bracket and the roller a spacer sleeve 63 and the assembly is held together by a nut 64 threaded on the other end of the axle 6|.

These roller-bracket assemblies are attached respectively to opposite sides of the table portion of a power-driven table saw S so that said saw maybe bodily suspended by said rollerbracket assemblies from said tracks 59 and 60 (see Fig. 3) with the table top 22 of said power-saw flush or in the same plane with the top surfaces a of the upper side rails 31. This is accomplished by securing the other leg, of the brackets 62 to a side edge of the table top t of the power saw S by any suitable detachable means, such as bolts 65. With the roller bracket assemblies so attached to the power table saw S as above described, it may beinserted through the front end of the bench upon the tracks 59 and 60 when the wing 44 is in the position shown in Fig. 3.

The power table saws of different makes vary slightly in dimensions and to compensate for this length of the bench and that the V-shaped track 60 will maintain the tool 36 of the table saw in a straight line in its movement so as to produce accurate cutting operations upon work resting upon the bench while the flat tread rollers 59 offer less friction in the movement of the saw and permit lateral movement as when a spacer 63 of a different length is required between the bracket element 62 and the wheel 59. v

The table power saw S moves by gravity from the front end of the bench to its rear end (i. e. from right to left in Figs. 1 2, 5 and 19) and, to this end, the two front end legs 30 of the bench are equipped at their lower portions with means for raising the front end of the bench sufiiciently to decline the bench from front end to back end (as shown particularly in Figs. 2, 5 and 8). This raising means may consist of a channel shaped member 66 having extensions 56a at two corners thereof that lie on opposite sides of the front surfaces of the front end legs 30 and are pivotedthe top of the bench the declination necessary for the reciprocation power table saw to gravitate to the rear end of the bench. Of course, it is 'understood that, when the leg extension members 66 are moved to its dotted line position (as shown in Fig. 8), the front end of the table must be manually lifted so that said extension member may be moved in position.

The power table saw S is moved for effective cutting operations from the rear end of the bench to thefron t end of'the bench, under the control of the operator, through means of a novel treadle mechanism T. The arrangement of this treadlemechanism is such that a relatively'small depressed and downward movement of the treadle 10 will traverse the saw S thev length of the bench. This treadle mechanism T is more particularly disclosed in Figs. 1, 2, 4, 5 and 8 and is shown as located adjacent the right front leg 30 of the bench to be accessible to the right foot of 'the operator and to apply its full force on the traveling power tool S at a point adjacent the V-shaped track 60 which guides the tool in its cutting movements.

The treadle mechanism '1 comprises a generally horizontally disposed treadle lever 'H pivoted at one end, as at Ha, to a plate support 12 secured to'the lower side brace rail 34 and the adjacent brace strut 52. The other end of the lever H extends forwardly beyond the front end of the bench for a desired distance so as to be accessible to the foot of the operator and carries thereon the treadle pedal 10. Above the treadleleve'r'll is disposed an arcuate throw-lever I3 pivoted at its lower end for a swinging movement in a vertical plane to a bracket 14 fastened on the adjacent leg 30. The convex surface of the throw lever 73 is positioned to ride upon a roller 15 journalled midway of the length of a pull-lever 16 also disposed for a swinging movement in.a vertical plane and whose lower end is pivotally connected to the lower end of the adjacent leg 30, as at 11, and also whose upper end carries a double sheave 18. The treadle lever H is connected with a throw-lever I3 by a link 19, the link being pivotally connected to the treadle-lever at a point intermediate the center of the treadle-lever and its pivot Ha, as

at 80, and having its other end connected to the throw-lever 13 at a point between the latters pivot point 14a and its contact with the roller 75 on the pull-lever 16. 'As particularly shown in Fig. 4 it will be noted that the throw-lever 13 may comprise two slightly spaced identical levers arranged co-extensively and pivoted at Ma and that the link 19 extends through a slot in the pull-lever 16 (which is channel-shaped) and projects between the two spaced throw-levers 13 where it is pivoted to the same on pivot 8011. It has been found that this lever arrangement, through a simple cable connection, enables a downward movement of three inches of the treadle pedal 10 to impart movement to the pulllever 16 that will cause the table t of the power tool device S to travel between 56 and 60 inches.

The; cable connection between the pull-lever and the power saw S comprises a cable 8| having one end connected at 82 to the pull-lever 16 and passing over a three-way sheave 83, fast to the adjacent leg 30, and over the two-way sheave 18, the other end 84 of the cable 8| being detachably connected, as at 84, to the spacer 63 surrounding the axle 6| of the front rollerbracket assembly on the track 60.

It is manifest that by gradually depressing the treadle 10 the power table saw S may be moved from its rearmost position toward the front end of the bench so that .the tool or saw 36 may operate upon the workby moving into the work haemati e w in" "m ,uer ,iiewriwargiiy -.ez itending vp n go, at its opposite jeejdgpbrtians gm Joe 'le'ctivel'y and tedly ea .e",e;1 Q.a,.,' tr, "ely iextjentling series of i h'eii .siia cea erien zigjsjql in opposit e por- 6 the,iipperjsurfacebi fthedrtag-leat 31, utt rin s J9 1 10h rq ii ee t e dyer leaf'be'ing aligned wit, a fcorfrespondingvopening etthe th -e d 1 5 th t .the a iefi be generally Iadji sted "to affect the apgqroggiieqfife t mer t. ..the ti tzt e ta e by theftb'ol "36, Asn anv holes}! nay bejprovided e h 21 9 li i de i-w r The holdihgha'r 385 carries a gaufge bar 92 v is ce 'eiite'nsive therewith and'i's'disposed o'nthe face-of the holdingharjiyna gnre 11 1 38, the gauge bar 92 be} suppbr t'e'd from the fielding tar '8'5 tyrvr anms sstiine positioned *o'p'pos'ite end, ioofrtio'r is o'f the holding 1 bar to at iv the gauge loar'to he moved toward and seem-hie holding bar 161' obtaining fine or accurate iiieasliretnent. Each of the -lever Farms 93 amends-through a slot :91! ."inFthe holding bar 85 and is pivoted thereto intermediate its ends,

as at $5, with one endof' theilevehfpivotally eon-mamas at '98-, to the -g'auge bar .92 ,.'and with its other end having a portion 93a extending throfigh an-arcuate slot 91 in a quadrant 9 8 fastened to the ho1diiigbarr85, An edge of theihdldmg liar i's'provided. with 1 as may be necessary 1.0 the quadrant slot 91:- inay be provided with a 'scale if desired-and the end '93w of the lever 'is igrovided lv'vith ..'a 1 threaded hand-clamp '99. so that the -adjusted: position of the lever %93 may b'e' clainpdin' its ad'jiis'ted po'sition.

- Thefconstriiction-ot the 'rip-gauge; therefore, allow-s the gaiig'ebar 92 to be nicely iadjusted .in extended position mm the holding-bar 85 or allows the' gauge bar '92- to be moved in a juxtaposition-against the cIanip bar-. Also, it willvbe obvious that, should it be desir ed totake an oblique ripping put inr the material, the lever arms-$3 may be adjusted' to difierent angles for this fiuipose. Furthermorepthe length "of the arms {93 *between its pivots 95 and 196 may be siichas wilt allow full advantage-am be taken of "the 'g'auge to bring-the ga.uge bar 92 inf close 1 :i1foiirnityto the t'ool 36 when the clamping bar-"85 is i'n' its closest adjustment to the tool I As shown in the dr'a'wirigs, particularly "Figs. -13-"to 17 inclusive, the holding bar i85 may bev a z shapen etal bai andth'e clip 86 may also be z-snap'cr of smaller dimensions welded to the end of the bar 85-; and-the gauge barmayhe a 'in'etal channelfbarQo'faltihiinum or"other'r1ike 'me'talr "Suitablejian'dles I00 :may be provided 'onythe iipper ends ofithe pivots '95-andl96 to enable "a con ver i-ient handling and manipulation of ithe gaugelRG .t l

The work bench ot 'this invention is a lsoriprovided with a- 'cro'ss' -cut gauge-CG shown in'Figs. 19, 20 and 2 1. As is the case with theripgauge the-cross-cut gauge C G -is employed when the dropleaf '31-is in =its ho'fizontalpositioh Tana don"si'sts '01:: a holding -b ar l0l that is eqiiipped 'a't i tsfiriner end portion with asspaced i ndrqyihg c'li'p ior; flange I02 on its "under-surface which; is aldapted tq hook or -engage about the inner side edge-of thetop portion 'aiof .the iip'per side mm 1 oilthe Lb'ench; ::'I'he holdingiflbar I BI is designed to ext-enditherefromtransversely across the drop-leaf 31V vto aaflioin't .-Sh01t.'0f the of said tress-cut g'a-uge C'Gflisiequi-pped with a latch member 03rwhich thelsam'e as the {latch member '81 of the-ripping :gauge :RG and actuated By a's'iinilar clamp Clever HM :soithat the cross-cut "gauge can be clamped in locked position transversely of: the drope'leafr. t

H Also to assiireaecilrate positioningz'of the holding bar f!) l, thev under-side of. the holding ba'r l O l is provided. with .adownwa'rdly, extending pin's H15 which engage. in aligned-;openings;or holesttllfi. in the dropeleaf :31. which (will, align the cross-Zcut gauge. holding bar I'BI normal to the 'rnov'eme'ntof the tooli36. a fAs :ca'n be-seen .f-rom Figl-aflthe inne'rgend i illar of the -?cr0ss..-cut--ho'lding :bar .lfll :extends I about'half-way.acroSsthe area between the side rails 3l of-the work bench and has'a gauge-bar 0'? piVoted-tothib innerw ridthereof as at. [08, so thatthe gagge-bar I 01 may bemoved angularl y withrespect to the holding bar :HH. x-This angular adjustment ofthe gauge bar I 01 may be accomplished by a rod 1 09 pivo tally connected at IHl to the gauge'ba'r and-passing through an opening H in the holding bar [01 and through a clamping device ll2-fifor holding the rod I09 in adju'st'ed p'ositi'on. The rod I 09 may be provided also with a scale on its surface for giving clegreesof ang ul'arity. H

Th-31s, it; is-ohvious that; forordinary crosscutting purposes, the gauge ban I01 may- "be moved in juxta-p'osition against the holding bar a 11 1 Y IN and an edge of the work-material to be cross-cut, may be placed thereagainst; and, upon actuation of the treadle 10, the tool;36 may be moved into the material to effect the cut. Should it be desired to take a diagonal cut, as indicated in Fig. 19', the gauge ID'I may be suitably adjusted by actuation of the rod I09 to eflect the degree of angularity, which adjust- This extensible rod H3 may be adjusted to positions beyond the inner end of the gauge bar 5 I01 and held in adjusted positions by thumb screws H4. The outer extremities of the rod H3 carries alaterally extending projection So having a vertically adjustable inwardly extending flange 3b which forms 'a pocket for the corner of'the material M to be cut and with the flange 3b underlying the corner of said material so that, during the operation of the tool 36, said material-piece M' will not slip or slide out of position due to the angularity of the gauge ID! with respect to the direction of travel of: the tool. 1

The opposite end of the gauge bar may be provided with a slotted projection 1 [5 which will'extend through a complemental slot Set ,6,

in the holding bar llll, when the gauge bar is in juxta-position against the latter, and a pin or suitable wedge may be inserted in the slotof the projection I [5 to hold the'gauge bar in said juxtaposition and when the rod I09 is folded in parallel A relation with the holding bar lfll and out of engagement with its clamp H2.

To adapt hand saws to use with the bench of this invention, there is provided with the bench manner as do the brackets 62 previously de-ii scribed, thus eliminating'the necessity for the bracket 62. The table top t is provided with the usual slot i through which may extend the saw blade or other rotatable tool 36a of the so-called, hand tool S. the underside of the table top t by three bolts I I6 which do not extend beyond the upper surface of the table top if and which enable the saw S to be readily attached and removed from the table top t.

In some instances, it is advantageous to employ the rotatable saws or tools 36 or 36a while in a stationary position on the bench; and, to this end, the tool may be moved by the treadle 10 to the position desired on the bench where it may be checked into stationary position by chocking blocks ll'l removably attachable to the track 59 and disposed against opposite sides of its wheels 59a, as shown particularly in Figs. 24 and 25. The chocking blocks consist merely of rectangular blocks, or their equivalent, having a The hand tool S is mounted to' .slot I I8 into which the track flange portion of i the track 59 is received and a hand set screw H9 threaded into one end of the block so as to impinge against the under-surface of the track and bind the block firmly in position. These blocks may also be employed for retaining the device S and S in stationary positionon the bench during shipment or transportation when desired.

From the above it will be manifest that the present invention provides an unique and improved mill bench for carpenters and other artisans which enables them to employ thereon powertools, now on the market, after the manner of the mill and that the bench is exceedingly light and can be moved about from place to place as desired and can be constructed and provided at reasonablecosts; The bench also affords a small portable mill for carpenters and the like which is safe'to operate, which is speedily, eflicient, accurate and time-saving and can be used by a single person without theneed of assistants to perform a multitude of operations, and which can be collapsed to be moved from room to room and power-tools; that the mill-bench is particularly useful in cutting operations with materials of wide and long dimensions and which is not possible in many cases with the presently available power table and hand tools or without the requirement of helpers; that said mill-bench is durable and strong and that the drop leaf thereof may, in addition to the functions specifically described, form a convenient work-bench.

To those skilled in the art it will also be apparent that the traveling saw or tool 35 and 36a, operable by the foot pedal under the full control of the operator, allows such work to be done as rip-cutting, cross-cutting, diagonal cutting, mitering, compound mitering, dadoing, grooving, chamfering, and shaping; and that such operation may be performed efiiciently upon plywood, Masonite, sheetrock and a large other variety of metals; and, by inserting difierent types of rotary tools, materials such as Transite, aluminum and sheet metals may be speedily out. Also, by attaching an acetylene cutting torch to the top surface of the table t or t, sheet metals and boiler plates may be accurately out without marking and in a safer and less dangerous manner of handling the torches.

Also, one or more power-driven drill presses may be positioned on the surfaces at of the upper side rails 3| to bore, ream or tap the workpiece; or a drill press may be mounted on the tables t or t and move along the workpiece; or by providing the table t or t with revolving tops upon which a drill press is mounted, a variety of operations may be performed on the workpiece by said drill press.

Having fully described the invention and the manner of performing the same and its advantages, it is to be understood that certain changes or variations may be made that fall within the spirit of the invention and that the invention is only to be limited by the scope of the terms of the appended claims.

That which is claimed, as new, is:

1. In a portable bench for reciprocably supporting automatic hand and table tools having an open area in its upper surface to form a guideway and extending longitudinally of the bench, tracks on the bench, one on each side of the guideway and extending longitudinally thereof, a roller supported bracket supported by each of said tracks and detachably connectible with a table element of an automatic power tool to be inserted in said guideway, the rollers of each bracket having an axle extending through the bracket, an interchangeable spacer sleeve surrounding the axle of each roller and interposed between the bracket and roller, and means for detachably fastening the end of the roller-axle to said bracket, whereby the distance between the roller and bracket may be varied to accommodate power-tools of different sizes.

2. In a portable bench, as set-forth in claim 1, wherein said bracket is substantially an inverted U with one leg having the axle secured thereto and the other leg adapted to be detachably secured to said table element.

3. In a portable bench for supporting automatic hand and table tools having an open guideway in its upper surface and extending longitudinally of the bench, carriage means mounted for reciprocal movement in and along said guide- Way for supporting an automatic power tool, means for reciprocating said tool including a vertical pull-lever pivoted at lower end to said bench and having a sheave at its free end, a sheave on the bench adjacent the path of movement of the free end of said pull-lever, a cable connected to said pull-lever and to carriage means and having its intermediate portions trained back-and-forth over said sheaves, a treadle mechanism to actuate said pull-lever and including a horizontally disposed treadle-lever pivoted at one end to the bench and having a pedal at its other end, an arcuate throw-lever opposite said pull-lever and having one end pivoted to said bench so that its convexed surface rides and bears against an intermediate 40 14 intermediate their ends but nearer their pivot points.

4. In a portable bench for reoiprocably supporting tools, means for reciprocating said tools and. including a pull-lever pivoted at one end to said bench, a throw-lever pivoted at one end to said bench and arranged in relation to said pulllever to have a side surface thereof to bear and ride against a side surface of said pull-lever to move the latter, a treadle-lever pivoted at one end of said bench-and having a pedal at its other end, a link connecting said treadle-lever and said throw-lever at points intermediate their ends, and an operable connection between the free end of the pull-lever and said tools.

THEODORE L. DIRKSEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 272,734 McDonald Feb. 20, 1883 287,124 Hamlet Oct. 23, 1883 658,999 Scannell Oct. 2, 1900 934,949 Trickey et al Sept. 21, 1909 1,756,527 Thompson Apr. 29, 1930 1,789,125 Wildersen Jan. 13, 1931 1,813,783 Tomlinson July 7, 1931 1,826,222 Peterson Oct. 6, 1931 1,864,840 Lehner June 28-, 1932 1,930,168 Hall Oct. 10, 1933 2,010,882 Ocenasek Aug. 13, 1935, 2,032,976 Carter Mar. 3, 1936 2,230,929 Bray et al Feb. 4, 1941 2,505,658 Wilson Apr. 25, 1950 2,515,008 Humphrey July 11, 1950 FOREIGN PATENTS Number Country Date 120,047 Switzerland May 2, 1927 

